If you’re building a small robot that can explore tight spaces, it would be nice if the device could squeeze through narrow gaps. An experimental new robot can do just that by emulating a caterpillar.
A 9 cm (3.5 inch) long soft-body robot is being developed at North Carolina State University by a team led by Professor Yong Zhu.
It is modeled after the caterpillar of mother-of-pearl moth (Pleurotia ruralis). Like other caterpillars, it moves back and forth by rolling body parts in turn. Body curls go either front to back or back to front. While caterpillars use their muscles to do so, robots use nanowire heaters.
Its body consists of two layers of different polymers. The top one expands when heated and the bottom one contracts when heated. The top layer is embedded with a network of silver nanowires and features multiple lead points along the length of the robot.
When a current is applied to any of these points, the nanowires in that area heat up, heating the surrounding polymer. This will cause the robot’s body to curl upwards in that area only. Therefore, by sequentially applying current to multiple adjacent lead points, it is possible to generate curls that flow up, down, left, and right along the body.
“We demonstrated that a caterpillar bot can pull itself forward and push itself backward,” said postdoctoral researcher Shuang Wu, lead author of the study. “In general, the more current you apply, the faster it will move in either direction. But there is an optimal cycle, giving the polymer time to cool down and effectively relaxing the ‘muscle’ before contracting again.” It turns out that “
By selectively activating nanowire heaters in front and behind the robot, the researchers were able to move the robot through a 30 mm (1.2 inch) long gap that was only 3 mm high. You can see the robot doing so in the video below.
“This approach to driving motion in soft robots is very energy efficient, and we are interested in exploring ways to make this process even more efficient,” Zhu said. “Additional next steps include integrating this approach to soft robotic locomotion with sensors or other technologies for use in various applications such as search and rescue equipment.”
The study is described in a paper recently published in the journal. scientific progress.
Robot caterpillar at North Carolina State University
Source: North Carolina State University
